You look great, your biceps are swelling and your pecs have almost popped the buttons off your shirt. But you still have a little too much bodyfat obscuring your abs, and when you walk up the stairs to your apartment, you huff and puff. If you have to carry grocery bags loaded with protein powder and canned tuna, you can hardly catch your breath. It's embarrassing.

Even worse, it's unhealthy. Your hard, muscular body belies an out-of-condition cardiovascular system. You can't put off that cardio program any longer. Sure, your real desire is to build muscle, but what good will a great physique do you if you can't get around to enjoy it and show it off? No more excuses that aerobics is for people who can't lift weights. On the contrary, a real aerobic workout will kick your butt to the moon and back.

Aerobics is an integral part of the bodybuilding lifestyle; whether in circuit training, fun cross-training activities, at home or in the cardio area of your gym, on machines or in the wide-open spaces. We will give you guidelines for everything from target heart rate to workout shoes. As for fat-burning, a key reason bodybuilders do aerobics, we separate the myth from the reality. Get ready to look better, feel better and be healthier with aerobics for bodybuilders.

Maybe you've heard that aerobics (also called cardio) burns up your hard-earned muscle. Truth is, the relatively small amount of cardio you need to condition your cardiovascular system won't flatten your muscles. In fact, aerobic activity will burn off fat and unneeded calories, revealing a tighter, leaner and more defined body. As added plusses, cardio work boosts metabolism, strengthens your heart and lungs, and lowers your risk of heart disease and certain cancers.

As a bodybuilder, your immediate interests probably include reducing your existing bodyfat and avoiding bodyfat gain. As you become better conditioned, aerobic training will help your cells become better fat-burning furnaces. This is related to improved insulin sensitivity, which could also lower your risk of adult-onset diabetes and certain cardiovascular problems.

Aerobic vs. Anaerobic
Running, cycling and swimming are aerobic activities; weightlifting, sprinting and boxing are not. During aerobic exercise, the heart rate rises, respiration increases and carbohydrates and fats provide working muscles with energy via oxidation. During anaerobic activity, the heart rate and respiration increase to a greater degree, but stored adenosine triphosphate (ATP) and creatine phosphate serve as primary energy sources. As a result, lactic acid accumulates in the muscles and blood.

Another way to understand the difference between aerobic and anaerobic work is to think in terms of duration and intensity. If you can do an activity for a relatively long time (at least 20 minutes), the intensity will have to be light to moderate so that you can keep it up. This is considered aerobic. Exercising at a high intensity so high that you cant continue at that pace for more than a minute or two at a time is anaerobic. But no exercise or activity is 100% aerobic or anaerobic. Sprinting may he anaerobic, while marathon running is aerobic, but when long-distance runners sprint for the finish line, they're activating their anaerobic metabolism.

As a bodybuilder, most, if not all, of the work you do at the gym is anaerobic. Yet what happens in your body as you recover between sets relates directly to aerobic metabolism and your level of aerobic conditioning. "Recovery of muscles challenged during lifting is expedited by a fairly good aerobic system," explains Jeffrey A. Potteiger, PhD, director of the exercise physiology lab at the University of Kansas in Lawrence. "During recovery, oxygen resynthesizes energy and rids the muscles of waste products like carbon, ammonia, lactate and so forth."

Just how much cardiovascular fitness is necessary to reap the maximum benefits? That question isn't so easily answered. "It depends upon several things, like intensity and duration of the cardio workout, fitness level, genetic makeup and what and when the last meal was, among other things," Potteiger says. But don't fret: You can still get the results you want without making the process an exact science.

Hit the Ground Running
No magic formula can determine the best cardio program for you. With all the variables involved, including your own preferences, you just need to try different activities to see what works. Abiding by a few guidelines, though, can help you get started in the right direction. Find which body type best describes you to get an idea of where to begin.

Endomorph: For the person who tends to gain and hold bodyfat easily, a challenging but safe cardio workout is a must. Choose activities that keep jarring of joints and tissues to minimum.
• "Stair-stepping and cycling are good choices for a heavier person,' Potteiger advises.
• Start slowly, 20-30 minutes in duration 3-4 times a week. Gradually increase frequency until you're up to 5-6 clays a week, then slowly lengthen the sessions.

Mesomorph: Being naturally muscular could also mean that you're overweight for your height. Just like the endomorph, you should stay away from aerobic activities that could potentially cause back anti joint problems. Potteiger calls the NordicTrack and cycling good choices.
• If you're new to cardio activities, start slowly, working up to 4-5 days a week, 20-30 minutes each session.
• Depending on your goals, you may wish to cycle the intensity of your workouts for better results.

Ectomorph: "Problems with walking and running may not he as prominent for a person who is naturally lean," say's Potteiger. But just like anyone else, you should find a mode of exercise that's enjoyable.
• If you're just starting out, keep your cardio sessions between 20-30 minutes 3-4 days a week at moderate intensity.
• As your aerobic fitness improves, increase the frequency and duration. You don't need to worry about excess bodvfat, but be careful not to overdo it. Too much cardio could bring you to the point of diminishing returns.

Finding the Zone
Long before Barry Sears turned "the zone" into a household phrase for a fat-loss plan, bodybuilders and other athletes had another meaning altogether for it. In aerobic terms, the zone is that area of intensity that most people should work in to maximize the benefits of their workouts. To improve fat metabolism, burn calories and increase the efficiency of your cardiovascular system, work in your target heart-rate zone.

The target heart-rate zone for a 30-year-old is 114-171 beats per minute.

If you're out of shape or have a health condition or are taking medication, be sure to check with your doctor about your target zone. Once you've determined what your zone is, you're ready to monitor your heart rate during exercising. Three of the most common ways to do so are:

Taking your pulse. About halfway through your aerobic workout, find your radial (near your wrist) or carotid (neck) pulse and count how many times your heart beats in six seconds. Multiply that number by 10 and you have your heart rate.Rate of perceived exertion (RPE). Because the heart rate formula above provides such a wide range, a good way to determine where you are in your zone is by perceived exertion, or how hard you feel you're working. On a scale of 1-20 (with 20 representing the highest intensity), you should work between a level of 13 and 15.Heart-rate monitor. A heart-rate monitor straps to your chest and transmits readout of your heart rate to your wristband. Starting at around $60, this method is both the most expensive and most convenient.

The Fat-Burning Myth
As a personal trainer and group fitness instructor, I'd be able to retire if I had a dime for every time someone asked me what burns more fat: a long, low-intensity workout or a shorter, high-intensity one. Unfortunately, this is a somewhat loaded question. The answer is: it depends. You have to work the numbers. "Short duration at high intensity could equal a long duration at lower intensity," explains Potteiger. "If the duration is the same, however, you'll burn more total calories if you work harder. High intensity burns more calories, including fat calories. Lower intensity burns fewer calories overall, but a greater percentage of them will be from fat."

Potteiger has another way of looking at it (remember that individuals burn calories at different rates depending on their size, metabolism and other factors, so these figures might not be precise for you):

But remember, you're walking longer than you're jogging to get these results. If you equalize the time factor and walk for 20 minutes, you'll burn 100 calories, of which 80 would be fat. So the jogging burns more fat. But if you can't or won't jog, the comparison is moot. You can get a good aerobic workout with brisk walking without jarring your knees, ankles and feet with repeated pounding.

Maximize the Benefits
Aerobic activity offers a wide variety of benefits to overall fitness and health. The visual improvements are great, but the long-term, more important advantages occur on the inside. Together with cardiovascular efficiency, metabolic changes will take you another step closer to achieving ultimate fitness.

You know aerobic exercise causes your body to burn calories, a percentage of which come from fat, depending upon (among other things) duration and intensity. But did you know that you continue to burn fat even after your 's workout is over? After training, the body needs to replenish muscle glycogen, and fatty acids help to manufacture ATP. Basically fat is used to partially refuel the body for its next burst of energy. The more intense the exercise, the more the body has to replenish, and the more fat it will use to do just that.

Now as far as your heart goes, aerobic exercise lowers your resting heart rate, increases stroke volume and improves the efficiency of the heart. A trained heart doesn't have to work as hard to deliver blood to the various parts of the body and can pump more blood with each beat than an untrained one. Aerobic training can also lower blood pressure, which in turn decreases the risk of heart attack. All this from just a few 30-minute cardio sessions a week. Pretty good, huh?

The best way to figure out the right aerobic program for yon is to first identify your goals. What results do you want from your efforts? Optimal fat-burning? Maximum cardiovascular benefits? Increased fitness?

Fat-burning/cardio health benefits. Generally speaking, a person should stay at the lower end of the target heart-rate range, but it depends on how long the person exercises," says Potteiger. "If the person is working out for only 20 minutes, the intensity should be up. If it's a 45-minute workout, the intensity can be lower."

Increased cardiovascular fitness. To increase heart and lung fitness that is, to improve cardiovascular efficiency stay at the middle to high end of our target heart-rate range, and keep the duration between 20 and 30 minutes.

Advanced/performance training. Training the body to work at a higher intensity before crossing over to an anaerobic energy system provides maximum endurance training as well as an opportunity to burn more calories than lower-intensity workouts (therefore burning more fat). This type of training requires you to work at the high end of your target heart-rate range.

Taking the Next Step: Working Out

1) Plug in the cardio sessions when you're most likely to stick to them.
2) For the first few weeks, keep the sessions short and sweet; 15-20 minutes 2-3 times a week. Increase your workload gradually. Warm up and cool down, and get enough water.
3) Choose activities that you really enjoy (at least avoid the ones you know you hate).
4) Record the details of each session (time, length, mode of exercise, how you felt). If you decide to make changes, you can compare the old program with the new.
5) Don't he afraid to make changes to discover what works best for you.